Permission from City of London.

To be able to film in London, it is courtosy to ask and let them know.
Here is the link for the website containing the information we need to know:
http://www.cityoflondon.gov.uk/Corporation/LGNL_Services/Leisure_and_culture/Arts_and_entertainment/guidelines.htm

On this link it clearly states "On the basis that you are filming with a small crew only (less than eight people), keeping to public walkway, are using portable equipment only and you will not cause any obstruction, danger or offence to others, then you are not obliged to submit an application. However it is deemed good practice to submit an application for all shoots and we advise you do so as we can then notify relevant parties such as the Police and Highways that you will be filming and in turn we can send you confirmation that we see no objection to your filming.''


So..technically, we dont need to do one. But we will attempt to get a reply from them anyway. 
 Here is where i got so far, however we needed insurance information which i didnt have... :/